1. Field of the Invention
The field of the invention is fresh cut flowers, fresh fruits and vegetables, and methods and compositions for maintaining their freshness and shelf life without refrigeration.
2. Description of Related Art
Since the beginning of mankind, agriculture has always played a major role in the everyday life of man particularly to fresh fruits and vegetables that are easily harvested. Modern agriculture has increased productivity in agriculture but has never reduced the huge losses in the post-harvest of fresh fruits and vegetables. These post-harvest losses are not new; they have always been a problem for mankind. In these days of rapidly enlarging populations in the poorest countries whose food supply is already short, the problem of post-harvest loses of fresh fruits and vegetables has become increasingly critical. Currently these post-harvest loses amount to thirty-five percent (35%) in industrialized countries to seventy percent (70%) in under developed countries.
In the early days of horticulture in today s industrialized countries, heavy losses occurred in much the same manner as they do today in developing countries. Increasing industrialization in technologically-advanced nations gradually brought improvements in crop handling. Elaborate harvesting equipment replaced the crude harvesting tools. Collection centers were strategically established in major producing areas. Containers were remodeled to add more protection to the fresh fruits and vegetables. Commercial storage plants were installed and grade standards adopted. Engineers and economists became more and more aware of raw material behavior. Advances in refrigeration technology in the developed countries made possible the establishment of cold chains for the entire post-harvest and handling operations. At the institutional level, post-harvest research was initiated. Pilot packing houses were installed, coupled with the development on intensive training programs. The improvement of product quality and reduction in post-harvest losses became the main concern of producers, middleman, marketing specialists and consumers. Today, enormous volumes of quality horticultural fruit and vegetable crops produced in technologically advanced countries are made available to millions of people through improved post-harvest handling. Thus, historically and by necessity, post-harvest technology is part of the normal development processes in agriculture.
These handling processes are not fully recognized in less-developed countries. In such countries, agriculture may be characterized as disjointed. Production is not linked with marketing. With highly perishable crops like fruits and vegetables, storage, packing, transport, and handling technologies are practically non-existent. Hence, considerable amounts of fresh fruits and vegetables are lost after harvest. Post-harvest, loss-prevention technology measures have become more important than ever.
It is distressing to note that so much time is being devoted to the culture of plants, so much money spent on irrigation, fertilization, and crop protection measures, only to be wasted about a week after harvest. It is, therefore, important that post-harvest technology and processes be given much more attention than current production practices.
Fresh fruits and vegetables have many similarities with respect to their compositions, methods of cultivation and harvesting, storage properties, and processing. In fact, many vegetables may be considered fruit in the true botanical sense. Botanically, fruits are those portions of the plant which house seeds. Therefore, such items as tomatoes, cucumbers, eggplants, peppers and others would be classified as fruits on this basis. However, the important distinction between fruit and vegetables has come rather to be made on usage basis. Those plant items that are generally eaten with the main course of a meal are considered to be xe2x80x9cvegetablesxe2x80x9d. Those that are commonly eaten as dessert are considered xe2x80x9cfruitsxe2x80x9d. This artificial distinction is made by the food processor, certain marketing laws, and the consuming public. Fruit contains natural acids, such as citric acid in oranges and lemons, malic acid of apples, and tartaric acid of grapes. These acids give the fruits tartness and slow down bacterial spoilage. Organic acids also influence the color of fruits since many plant pigments are natural pH indicators. Carbohydrates are the main component of fruits and vegetables and represent 90% of their dry matter. Water is also present in fruits (between 80 to 90%) and in vegetables (generally, between 90 to 96%). More mineral substances are present in vegetables than in fruits; but enzymes that are present in all fresh fruits and vegetables are the biological catalyst that promote most of the biochemical reactions which occur in fresh fruits and vegetables.
Some properties of enzymes in fresh fruits and vegetables are the following.
1. In living fresh fruits and vegetables, enzymes control the reactions associated with ripening.
2. After harvest (unless destroyed by heat, chemicals, or some other means), enzymes continue the ripening process. In many cases, fruit ripens to the point of spoilage, such as soft melons or overripe bananas.
3. Because enzymes enter into a vast number of biochemical reactions in fresh fruits and vegetables, enzymes may be responsible for changes in flavor, color, texture, and nutritional properties.
4. The heating processes in fresh fruits and vegetables manufacturing and processing are designed not only to destroy micro-organisms, but also to deactivate enzymes and so improve the fruits and vegetables storage stability.
Once the fruit or vegetable has left the tree, the organoleptic properties, nutritional value, safety, and aesthetic appeal of the fruit deteriorates in varying degrees. The major causes of deterioration include the following:
(a) growth and activity of micro-organisms;
(b) activities of the natural food enzymes;
(c) insects, parasites, and rodents;
(d) temperature, both heat and cold;
(e) moisture and dryness;
(f) air and in particular oxygen;
(g) light; and
(h) time.
The rate at which foods spoil, if proper measures are not taken, is indicated in table 1.0 below. The table shows the time in days of the generalized storage life at seventy degrees Fahrenheit (70xc2x0 F.) with a normal humidity of 60%.
Flowers are a colored, sometimes scented, part of a plant that contains its reproductive organs. It consists of a leafy shoot with modified leaves, petals, and sepals surrounding male or female organs, stamens, and pistils. There are about 200,000 species of flowers, classified in many different families. However, only about 1,000 flowers are used commercially worldwide due to the short shelf life associated with them. The most common uses are horticultural, ornamental and as gifts (such as roses), gastronomical reasons (such as lettuce and artichoke), or as vegetable oil (like sunflower oil). Flowers are grouped into an inflorescence (flower cluster) called the head, or capitulum, which resembles, and functions as, a single flower. The flowers within the head are called florets. There are two types of florets. The first, called a disc floret, has a tubular corolla (set of petals) with equal lobes. The second type, called a ligulate or ray floret, has one side of the corolla tube extended at the apex to form a long, petal-like strap. The calyx (floral envelope) that surrounds the individual floret in a head is usually reduced to a ring of scales or bristles called the pappus, which often aids the distribution of seeds. In the common dandelion and thistles the pappus consists of fine bristles that enable the fruit to float through the air. In other species it is barbed, causing the fruit to stick to passers-by. The anthers (pollen-producing parts) are joined to form a tube through which the style (part of the female flower part) extends. The anthers release the pollen into the tube, and as the style elongates it pushes the pollen upward out of the tube, making it available to insect pollinators or to wind dispersal. The stigmas (pollen-receiving areas) of the style are located on two branches of the style tip, and these branches separate after elongation. Thus, self-pollination is usually avoided, although in some instances pollen travels backwards into the pollen-bearing anther tube to allow this to occur. The pistil (female flower part), which has a single ovary, bears the other flower parts on its apex. After fertilization it matures into a hard-coated fruit that bears a single seed. Plants like humans also have need for water. If flowers do not receive water, they will and ultimately due. For some plants, such as tomatoes, a quick watering revives them within a few minutes to an hour, whereas more sensitive plants may never recover. Unlike animals, plants do not have a rigid skeleton. Woody plants, such as trees and shrubs, have hardened cell walls with secondary growth to give them rigidity. Herbaceous plants, on the other hand, have very flexible cell walls which are rigid only when the plant""s cells are filled with water. Animal cells under the same amount of internal pressure would burst, but plant cell walls are much stronger and easily withstand this pressure, which is called turgor pressure. In order to maintain turgor pressure plant cells need an ample supply of water. Plants continuously lose some of their water through a process called transpiration. Like all organisms, plants must breathe. Air is exchanged through small openings called stomata (stoma, singular), located on the undersides of leaves. Stomata can be opened or closed by a special pair of cells called guard cells. Unfortunately, not only does air pass in and out, but also water. On a hot day especially large amounts of water can be lost. If the plant is unable to replenish the water being lost the guard cells begin losing their turgor pressure. Soon thereafter, if water is still unavailable the plant wilts as many other cells begin losing their turgor pressure. There are many adaptations used by plants to prevent water loss than in addition to the simple approach of closing the stomata. One of the more familiar approaches is to store large amounts of water either in the stem, as in cactus or cacti, or in the leaves and stem, as in stonecrops (sedum) and other succulents. A natural waxy leaf covering is effective in preventing water loss in some plants. The common sagebrush, as well as a number of other desert and chaparral plants, often have dense, light colored hairs covering the leaves. This prevents not only water loss, but deflects some of the sun""s heat, which can also prevent evaporation. Even more intricate mechanisms are used by some plants. The stonecrops and other members of the Crassulacea,e among a number of plants in other families, use a special type of photosynthesis called Crassulacian Acid Metabolism or CAM. This alternate photosynthetic mechanism allows the plant to open their stomata at night, while keeping them closed throughout the day, when water loss would be at worst. Still other plants simply avoid the whole water problem by either growing only when water is abundant (so-called ephemerals) or by becoming entirely aquatic as in pondweeds (Potamogetonaceae) or pond lilies (Nymphaeaceae). In fact, aquatic species occur in most flowering plant families. An specially big challenge for most plants is obtaining water from salty soil or saltwater. Very few plants can tolerate very much salt in their surroundings. First, molecules of any substance have a tendency to migrate from areas of high concentration to areas of low concentration. This phenomenon is called diffusion and is best observed by dropping a small amount of red food coloring into a glass of water. After a few hours, even without agitating the water at all, the food coloring diffuses evenly throughout the water. Water also diffuses from areas where there there is more water to areas where is less water. In water this process is referred to as osmosis. In saltwater there is less water per given volume then there is in pure water. If some pure water is separated from some saltwater by a membrane that allows just water to pass and not salt, and interesting phenomenon occurs. Water gradually flows from the pure waterside into the saltwater side. In fact, it will continue to flow, but when a moderate amount of pressure is applied the flow will stop, the amount of pressure required being a measure called osmotic pressure. We can apply this concept to what happens to a plant in wet soil. If the water in the soil is fairly pure, with only a small amount of salt and other dissolved material, water will tend to flow from the soil into the roots of the plant. This is because the water already in the plant root has a lot more solid matter dissolved in it and the water flows from the fairly pure soil water to the soupy water already in the root by osmosis. In salty soil the situation is reversed. The soil water now has more dissolved in it than the water in the root and osmosis is reversed. Water flows out of the root into the soil. As a result the plant wilts and eventually dies from lack of water, even though there may be large amounts of water around. Some plants have adaptations which allow them to survive in the presence of large amounts of salt. Surf grass and eel grass (both Zosteraceae) are two flowering plants that actually live submerged in saltwater, keeping the salt concentrations in their leaves and roots fairly similar to the surrounding seawater. Mangroves comprise a large number of species whose roots are bathed in saltwater as well. Others, like pickleweed, can tolerate even higher levels of salt found in the twice-daily exposed soils of the salt marsh. They accomplish this feat by keeping salt concentrations within their stem and roots even higher than the surrounding water in the salt marsh soils. Saltgrass, a little less tolerant, survives the high salt concentrations in soils above the high tide line by excreting salt on the surfaces of their leaves. Other plants, less salt tolerant, are still capable of surviving in soils that are deadly to most plants. Plant breeders are very interested in how halophytes deal with salty soil. It is hoped that some of the genes responsible for salt tolerance will be located so that they can be put into important crop plants. If important crop plants could be developed to have salt tolerance, many currently unusable land could be farmed. Irrigated land gradually builds up salt and eventually becomes unusable, and such genetically engineered plants could prolong the life of irrigated land. Most cactus do come from warm weather low rainfall areas of the world although there are exceptions. There are no known fossils of cactus, and it is not known with certainty when they developed the unique adaptations that enable them to live in the harsh environments that many of them survive in. Many scientists believe that the cactus developed their physiological traits in response to changing climatic conditions several million years ago. The major traits that people see when they first observe cactus is the abundance of spines in many species. These spines serve several uses. They guard against most browsing herbiverous animals by making the plant difficult and dangerous to chew. The spines also help to shade the plant, helping keep internal heat down. Finally the spines also can channel the infrequent rains to the base of the plant. Another easily identified characteristic of many cactus is a waxy coating that surrounds the plant over the skin, which often has a bluish cast to it, and may be damaged by careless handling. This is called a glaucus bloom and helps to reduce evaporation by the plant. This holds in more of the precious moisture so rare in the desert. All advanced plants have leaf holes called stomata. These holes are what open to permit entry and exit of various gases and moistures. Un cactus these stomata close tighter than in most plants further reducing the loss of moisture in the heat of the day. Another thing that cactus can do is to store up lots of water when it does fall. Many have the ability to open themselves up accordion style to hold massive amounts of water. Then when the plant is losing water, the pleats of the accordion fold up shading the plant more and reducing surface area exposed to the sun. When the plant is stressed and not getting enough water it will often bend over as the hygroscopic (water filled) pressure inside the plant diminishes. The hygroscopic pressure is what holds the plant up erect. As it lessens the plant loses its rigidity and can no longer stand erect. As it bends over its exposure to the sun is reduced, much of it is shaded by the overhead portion such that moisture loss is further lessened. Root behavior is another adaptation that cactus have made in order to live. They tend to have roots that spread laterally for quite a ways and may exist in a suspended state until the rains activate them, a small amount of moisture will cause the feeding roots to quickly grow out from the main roots. These feeders bring in the water and its dissolved minerals and nutrients. After the rain is gone and as the soil dries these feeder roots die and disappear enabling the plant to live on its stored water without having to spend energy and moisture keeping these roots alive that may not be needed for many, many months. The above mentioned main characteristics of flowers are relevant to the reader to understand the purpose of this invention and the principles taught in my U.S. Pat. No. 6,123,968. The instant invention is to a process to create a composition, and the resulting composition for extending the shelf life of fresh cut flowers and fresh fruits and vegetables without the use of refrigeration. Fresh cut flowers, like fresh fruits and vegetables are also lost in enormous quantities worldwide once they are severed from the mother plant, i.e. harvested. Thus, there is clearly a worldwide need for the present invention in that it is going to dramatically reduce, and in some cases eliminate the need for refrigeration between harvest and consumption.
As soon as produce is harvested, the processes leading to breakdown begin, and cannot then be stopped; the rate at which breakdown occurs can, however, be slowed to minimize losses. The most common commercial methods to slow down the enzymatic processes follow:
1. Refrigeration at all points of receiving, distributing, and retailing the fresh fruit, flowering plants and vegetables. Although, this is a very expensive method, it is the most common. Only 15 to 20% of all harvested fruits, flowering plants and vegetables use refrigeration.
2. Care to prevent cutting or bruising of the fruit, flowers and/or vegetables during picking or handling.
3. Packaging or storage to control respiration rate and ripening of fruits, flowers and vegetables.
4. Use of preservatives to kill micro-organisms on the fruits, flowering plants and vegetables. In other words, fungicides are applied as food waxes and other applied substances to supposedly improve the appeal of the fruits, flowers and vegetables with consumers.
Fruits can be classified as climacteric and non-climacteric. Climacteric and non-climacteric refers to two distinct patterns of ripening. In non-climacteric fruits the process of maturation and ripening is a continuous but gradual process. In contrast, climacteric fruits undergo a rapid ripening phase when triggered by enzymatic changes. The onset of climacteric ripening is thus a well-defined event marked by rapid increase in the rate of respiration and the natural evolution of ethylene gas by the fruit at a point in its development known as the respiratory climacteric. The importance of the respiratory climacteric is that fruits such as bananas may be held at a reasonable temperature when in the green state, but, as they begin to ripen, they will rapidly increase their respiration and generate much more heat. The consequence may be that this heating cannot be controlled and even more respiration will occur in a chain reaction, rapidly leading to spoilage of the fruit in a very short time. Once climacteric fruits start to ripen, very little can be done except to market them for immediate consumption. Ethylene is present in all fruit and is recognized as the central fruit ripening hormone which, in climacteric fruits, can actually initiate ripening when present at concentrations as low as one-tenth to ten parts per million (0.1-10 ppm).
Non-climacteric fruits also respond to ethylene application by increasing their respiration rate. However, the actual ripening process is triggered by the fruit itself. As well as being involved in ripening and increasing the respiration in fruits, ethylene also plays an important role in all plant materials and is produced in response to stress from wounds and injuries. In other words, ethylene produced by wounding or stressing may also trigger ripening in the damaged fruit as well as the undamaged fruits around it. Damage one green fruit in a box and the whole box load may ripen prematurely.
For this reason, good ventilation of fresh fruits with fresh air, refrigerated if necessary, is vital to ensure that ethylene levels do not build up to significant levels during storage and transport. Ethylene can also adversely affect certain vegetables. Carrots for example develop bitter flavors. Parsley and other leafy herbs will rapidly wilt when exposed to ethylene in stores and during retail display. Table 1.1 gives listings of common climacteric and non-climacteric fruit and vegetable fruits.
For all of the above-mentioned reasons and facts, the huge losses of fresh fruits and vegetables are a worldwide problem that needs to be solved with an inexpensive and simple method of application. Thus, there is clearly the worldwide need for the present application in that it is going to create an impact as large as the introduction of refrigeration to the worldwide, fresh fruit and vegetable industry.
The invention applies a process that naturally the enzymatic processes of ripening that occur in all fresh flowers, fruits and vegetables. The invention encompasses methods of making solutions, the solutions themselves, and the methods of using the solutions.
The invention also applies a process that naturally extends the shelf life without much water usage and without much moisture and also without the use of refrigeration for fresh cut flowers and fresh fruits and vegetables once they have been removed from the mother plant.
The naturally-occurring process being harnessed is the retarding of ripening in flowers/flowering plants, fruits and vegetables. Enzymes are protein catalysts that regulate chemical reactions in flowers/flowering plants, fruits and vegetables. Fruits and vegetables contain enzymes that advance ripening. Flowers/flowerings plants, fruits and vegetables also contain enzymes that retard ripening. The enzymes that advance and the enzymes that retard tend to offset each other. In most flowers/flowering plants, fruits and vegetables, both types of enzymes are present. An object of the invention is to harness and/or re-create the effect of the enzymes that retard ripening. Another object of the invention is to reduce or eliminate the effects of the enzymes that advance ripening.
In certain flowers/flowering plants, fruits and vegetables, the ratio of positive enzymes versus negative enzymes is greater than one. The flowers/flowering plants, fruits and vegetables with greater ratios are better suited for raw materials used to prepare the solution. Examples of fruits having greater ratios are limes, garlic, and onions. The following fruits and vegetables have been found to have produced efficacious solutions: limes, oranges, grapefruits, lemons, tangerines, pineapples, onions, and garlic. Cactus solutions made from combinations of the above-listed fruits and vegetables also work. The best time to process the fruits and vegetables to make a solution is when the fruits and vegetables have just ripened.
Also, some of the natural ingredients of the solution made out of fresh lime peels are very effective in controlling or killing surface bacteria, mold, and yeast which also can shorten the lifetime of the fruit.
Also, the naturally-found ingredient, d-limonene, is an excellent insect repellent. D-limonene is in relatively-high concentrations in limes. This also will increase the lifetime of the fresh fruit due to a lessening of the susceptibility of the skin to attack. Flying insects rarely attack a lime tree or the limes within the lime tree because they contain d-limonene.
The fruit enzymes are responsible for the many changes to the color, the odor, the taste, and the ripening of the fresh fruits. Once these enzymes become neutralized by other enzymes, the shelf life of the fresh fruits and vegetables can be extended from three to eight weeks depending on the fruit. The metabolism of the fruit will slow down by about 90%, causing the ripening and decaying process to slow down.
A method of producing the solution involves the following steps. First, the juice is extracted from the a part or parts of the plant, fruit or vegetable. Next, the juice is filtered. Next, any remaining parts are disintegrated. Next, the enzymes in the disintegrated parts are extracted with a solvent. The solvent should be chosen by its ability to dissolve as much of the enzymes as possible, while not dissolving the other flower, fruit or vegetable components. The solvent should not denature the enzyme. A ten-percent (10%) aqueous ethylalcohol solution is an example of a suitable solvent. Next, the disintegrated parts should be stirred in the solution allowing for full absorption of the enzymes into the solvent. Next, the solution and any disintegrated parts should be separated by a suitable method such as filtering. Next, the juices separated earlier can be added to the solution. The amount of dilution is governed by factors such as the method of application and the type of flower, fruit or vegetable being protected. Next, color agent(s) can be added to the solution to improve the solution aesthetically. Next, a wax or other application can be dissolved into the solution. The wax agent helps the application of the solution to the flower, fruit or vegetable and its adhesion to the flower, fruit or vegetable. Next, the solution can be quality controlled. In quality control, the amount of enzymes can be verified as well as any other ingredients. In addition, during quality control, the amount of contaminants can be verified. Finally, the solution is packaged for use or distribution. Because the solution utilizes plant enzymes that denature at around one hundred-thirty degrees Fahrenheit (130xc2x0 F.), the process of making the solution is always done near room temperatures. The results retain ninety to ninety-five percent (90-95%) of the enzymes that are found in the natural state of the extracted flower, fruit or vegetable.
In accordance with these and other objects which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings.